Simplified fluidic oscillator for controlling aerodynamics of an aircraft

ABSTRACT

Method and apparatus for controlling the aerodynamics of an aircraft using an active flow control system is disclosed herein. In one example, the active flow control system includes an airframe and a plurality of fluidic oscillators. The airframe includes an inlet configured for flight speeds ranging from subsonic to hypersonic. The plurality of fluidic oscillators is mounted about a curvature of the airframe. Each fluidic oscillator includes a body and an integral nozzle coupled to the body. The body has an inflow portion and a narrow nozzle inlet formed opposite the inflow portion. The integral nozzle is coupled to the body by the narrow nozzle inlet. The narrow nozzle inlet forms a single fluid flow path from the inflow portion to the narrow nozzle inlet.

GOVERNMENT RIGHTS

This disclosure was made with Government support under contract numberN00014-14-1-0014 awarded by the United States Navy. The government hascertain rights in this disclosure.

BACKGROUND

The present disclosure relates to fluid flow for an aircraft, and morespecifically, to a method and apparatus for controlling the aerodynamicsof an aircraft using a fluidic oscillator.

In operating an aircraft, fluid control systems may be used foroperation of the aircraft and components within or on the aircraft. Thefluid control systems are used during different phases of the operation.For example, the fluid control systems may be used during take-off, inflight, landing, taxiing on the runway, or during other phases ofoperation while the aircraft is in service. The fluid control systemsare used to control the flow of fluid over, in, or through variousportions of the aircraft during these phases of operation.

Traditional passive vortex generators, such as vanes and ramps, havedemonstrated partial success in controlling separation and improvingperformance in diffusers. A drawback to the traditional passive vortexgenerators, however, is that they obstruct the flow path, and therefore,always introduce total pressure loss and increased drag. Additionally,the traditional passive vortex generators are tuned to specificoperation conditions, and are not easily made flexible to provideperformance improvement across an operating envelope.

Conventional active flow controllers, such as synthetic jets, steadyjets, and traditional fluid control actuators, have been shown to beeffective at controlling flow separation. These active flow controllersare also capable of being integrated flush with the diffuser so as tonot introduce flow obstruction paths. However, the drawback to theconventional active flow controllers is that the performance improvementmargins from the passive vortex generators are often not great enough tooffset the cost and complexity of installation of the conventionalactive flow controllers. Thus, the difficulty in installation and highcost of manufacture result in fluid control systems below optimal levelsof performance.

SUMMARY

An active flow control system for an aircraft, according to a firstexample, is disclosed herein. The active flow control system includes anairframe and a plurality of fluidic oscillators mounted about acurvature of the airframe. The airframe has an inlet configured forflight speeds ranging from subsonic to hypersonic. Each fluidicoscillator includes a body and an integral nozzle. The body has aninflow portion and a narrow nozzle inlet formed opposite the inflowportion. The integral nozzle is coupled to the body by the narrow nozzleinlet. The narrow nozzle inlet forms a single fluid flow path from theinflow portion to the narrow nozzle inlet.

The active flow control system for an aircraft according to the firstexample, wherein the integral nozzle includes curved sidewalls angledwith respect to the narrow nozzle inlet.

The active flow control system for an aircraft according to the firstexample, wherein the angled curved sidewalls create a jet of fluid in athroat of the nozzle.

The active flow control system for an aircraft according to the firstexample, wherein the formation of the single fluid flow path reduces asize of the fluidic oscillator by at least a factor of 2.

The active flow control system for an aircraft according to the firstexample, wherein the formation of the single fluid flow path reduces aweight of the fluidic oscillator by at least a factor of 2.

The active flow control system for an aircraft according to the firstexample, wherein an angle formed between the nozzle and the body of thefluidic oscillator is less than 90 degrees.

The active flow control system for an aircraft according to the firstexample, wherein the plurality of fluidic oscillators are mounted abouta curvature transition of the airframe, upstream of a flow separation.

Moreover, aspects herein include any alternatives, variations, andmodifications of the preceding arrangement of configurations of theactive flow control system for an aircraft recited above.

An apparatus for managing flow control, according to a second example,is disclosed herein. The apparatus includes a body and an integralnozzle. The body has an inflow portion and a narrow nozzle inlet formedopposite the inflow portion. The integral nozzle is coupled to the bodyby the narrow nozzle inlet. The narrow nozzle inlet forms a single fluidflow path from the inflow portion to the narrow nozzle inlet.

The apparatus for managing flow control according to the second example,wherein the integral nozzle includes curved sidewalls angled withrespect to the narrowed nozzle inlet.

The apparatus for managing flow control according to the second example,wherein the angled curved sidewalls create a jet of fluid in a throat ofthe nozzle.

The apparatus for managing flow control according to the second example,wherein the formation of the single fluid flow path reduces a size ofthe fluidic oscillator by at least a factor of 2.

The apparatus for managing flow control according to the second example,wherein the formation of the single fluid flow path reduces a weight ofthe fluidic oscillator by at least a factor of 2.

The apparatus for managing flow control according to the second example,wherein the narrow nozzle inlet has a first diameter and the integralnozzle has an outlet, formed opposite the narrow nozzle inlet, having asecond diameter less than the first diameter.

The apparatus for managing flow control according to the second example,wherein an angle formed between the nozzle and the body of the fluidicoscillator is less than 90 degrees.

Moreover, aspects herein include any alternatives, variations, andmodifications of the preceding arrangement of configurations of theapparatus for managing flow control recited above.

A method for managing flow of a fluid, according to a third example, isdisclosed herein. The method includes receiving a fluid flow into aninflow portion formed in a body of a fluidic oscillator, transmittingthe fluid flow from the inflow portion of the fluidic oscillator to anarrow nozzle inlet formed in the body, opposite the inflow portion,along a single fluid flow path, creating a jet of fluid from the fluidflow in a throat of a nozzle, the nozzle integral with the body at thenarrow nozzle inlet, and causing the jet of fluid to exit the nozzle ina direction that changes periodically with time.

The method for managing flow of a fluid according to the third example,wherein the integral nozzle includes curved sidewalls, angled withrespect to the narrow nozzle inlet, configured to change the directionof the fluid as the fluid exits the nozzle.

The method for managing flow of a fluid according to the third example,wherein the single fluid flow path reduces a size of each fluidicoscillator by at least a factor of 2.

The method for managing flow of a fluid according to the third example,wherein causing the jet of fluid to exit the nozzle in a direction thatchanges periodically with time at a low frequency causes the fluidexiting the outlet of the nozzle to sweep across exit of the integralnozzle.

The method for managing flow of a fluid according to the third example,wherein causing the jet of fluid to exit the nozzle in a direction thatchanges periodically with time at a high frequency causes the fluidexiting the outlet of the integral nozzle to mix jet-energy with asurrounding fluid flow-field.

The method for managing flow of a fluid according to the third example,wherein the single fluid flow path reduces a weight of each fluidicoscillator by at least a factor of 2.

Moreover, aspects herein include any alternatives, variations, andmodifications of the preceding arrangement or configurations of themethod for managing flow of a fluid recited above.

The features, functions, and advantages that have been discussed can beachieved independently in various embodiments or may be combined in yetother embodiments further details of which can be seen with reference tothe following description and drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 illustrates a conventional fluidic oscillator for controlling theaerodynamics of an aircraft.

FIG. 2 illustrates an improved conventional fluidic oscillator forcontrolling the aerodynamics of an aircraft, according to one example.

FIG. 3 illustrates an aircraft having an active flow control system forcontrolling the aerodynamics of the aircraft, according to one example.

FIG. 4 illustrates a cross sectional view of a portion of the aircraftin FIG. 3, according to one example.

FIG. 5 illustrates a method for managing flow of a fluid, according toone example.

DETAILED DESCRIPTION

FIG. 1 illustrates a conventional fluidic oscillator 100 for use in anaircraft. The fluidic oscillator 100 includes a body 102 and an integralnozzle 104 coupled to the body 102. The body 102 includes an inflowportion 106 and a narrow nozzle inlet 108 formed opposite the inflowportion 106. The narrow nozzle inlet 108 couples the nozzle 104 to thebody 102.

A feedback control loop 110 is formed in the body 102 of the fluidicoscillator 100. The feedback control loop 110 is configured to create anoscillating jet of fluid that exits the fluidic oscillator 100 throughthe nozzle 104. The feedback control loop 110 includes a plurality offeedback channels 112, 114. When a fluid enters the fluidic oscillator100 through the inflow portion 106, the fluid is split between thefeedback channels 112, 114, forming two fluid flow paths: a first fluidflow path 116 through the first feedback channel 112 and a second fluidflow path 118 through the second feedback channel 114.

The first fluid flow path 116 and the second fluid flow path 118 exitthe fluidic oscillator 100 through the nozzle 104 in an alternatingfashion. Assuming that the fluid initially travels along the first side120 of the body 102, the fluid will follow the first fluid flow path 116through the first feedback channel 112 to the nozzle 104. The fluidexits the nozzle 104 along a second side 124 of the nozzle 104. Thefluid exits the nozzle 104 along the second side 124 of the nozzlebecause of the direction of the fluid delivered by the first feedbackchannel 112. Similarly, assuming the fluid initially travels along thesecond side wall 122 of the body 102, the fluid will follow the secondfluid flow path 118 through the second feedback channel 114, and exitthe nozzle 104 along a first side 126 of the nozzle. The fluid enteringthe inflow portion 106 will alternate following the first fluid flowpath 116 and exiting the nozzle 104 along the second side 124 of thenozzle 104 and following the second fluid flow path 118 and exiting thenozzle 104 along the first side 122 of the nozzle 104, thus creating anoscillating jet of fluid exiting the nozzle 104.

When operating at a high pressure ratio greater than 2.0, the flowphysics associated with the high pressure ratio chokes the throat of thefluidic oscillator 100, which negates the influence of the feedbackcontrol loop 110. The jet of fluid relies on the curvature of the nozzle104 to exit the fluidic oscillator in an oscillating manner. Thus, athigh pressure ratios, the feedback control loop 110 proves to beunnecessary, and needlessly adds size and weight to the fluidicoscillator 100, and results in difficult aircraft integration due to itscomplicated design.

FIG. 2 illustrates an improved fluidic oscillator 200 for use in anaircraft, according to one example. The fluidic oscillator 200 includesa body 202 and an integral nozzle 204 coupled to the body 202. The body202 includes an inflow portion 206 and a narrow nozzle inlet 208 formedopposite the inflow portion 206. The narrow nozzle inlet 208 couples thenozzle 204 to the body 202. The nozzle 204 includes curved sidewalls 210and an outlet 212. The curved sidewalls 210 are angled with respect tothe narrow nozzle inlet 208. For example, the curved sidewalls 210 maybe angled between 0° and 90° with respect to the narrow nozzle inlet208. In a specific example, the curved sidewalls 210 are angled at about31° with respect to the narrow nozzle inlet 208. The outlet 212 isformed in the nozzle 204 opposite the narrow nozzle inlet 208. Theoutlet 212 is sized such that the outlet 212 has a diameter 214 largerthan a diameter 216 of the narrow nozzle inlet 208. For example, thediameter 214 of the outlet 212 may be about 0.04 inches and the diameter216 of the narrow nozzle inlet 208 may be about 0.02 inches. The areaenclosed by the narrow nozzle inlet 208 is referred to as the geometricthroat 260 of the nozzle 204.

A single fluid flow path 218 is formed in the improved fluidicoscillator 200 from the inflow portion 206 to the outlet 212. As thefluid entering the fluidic oscillator 200 through the inflow portion 206reaches the narrow nozzle inlet 208, a jet 250 of fluid may be formed inthe nozzle 204. The jet 250 of fluid is formed provided that the fluidenters the narrow nozzle inlet 208 at a minimum pressure ratio, such asa pressure ratio greater than 2.0. The minimum pressure ratio chokes thethroat 260 of the fluidic oscillator 200, resulting in a Mach number ofunity at the throat 260. The formation of the jet 250 in the nozzle 204between the sidewalls allows the fluid to exit the nozzle 204 in anoscillating matter. This is due to the space formed between the jet 250and the sidewalls 210 of the nozzle 204. Therefore, the need for afeedback control loop, such as in a traditional fluidic oscillator 100,is no longer needed. The removal of the feedback control loop increasesvehicle integration potential and reduces fabrication complexity andcost compared to conventional devices and systems. For example, removingthe feedback control loop reduces the size and the weight of thetraditional fluidic oscillator by at least a factor of 2. These gainsare realized without compromising the benefit of the jet exiting thenozzle.

FIG. 3 illustrates an aircraft 300 having an active flow control system301 for controlling the aerodynamics of the aircraft 300, according toone example. The aircraft 300 is one example of an aircraft in which theactive flow control system 301 may be implemented as an active flowcontrol system for controlling the aerodynamics of the aircraft. Theflow control system may be implemented in the aircraft 300 to performvarious functions, such as maintaining desired airflow. For example, theflow control system 301 may be used to maintain desired airflow such asa boundary layer over a wing or stabilizer of the aircraft 300. In theexample shown in FIG. 3, the fluid control system 301 is implemented tocontrol the flow of fluid beneath a wing of the aircraft 300.

The flow control system 301 includes an airframe 302 positioned beneatha wing of the aircraft 300. In the embodiment shown in FIG. 2, theairframe 302 is a diffuser. The diffuser 302 includes an s-shapedelongated body 304 having a first end 306 open to ambient air and asecond end 308. The second end 308 is an aerodynamic interface plane,where the second end 308 of the diffuser 302 meets the compressor of theaircraft 300. The diffuser 302 is coupled to an inlet 310 at the firstend 306. An interface 311 of the diffuser 302 and the inlet 310 forms athroat region 312. The diffuser 302 and inlet 310 are configured forflight speeds ranging from subsonic to hypersonic.

As a fluid enters the inlet 310 and flows through the diffuser 302, thefluid has a tendency to separate from the surface. The flow separationoccurs when the fluid becomes detached from the inner surface of thediffuser 302, and forms eddies and vortices within the diffuser. Theflow separation results in increased drag, such as pressure drag, whichis caused by the pressure differential between the front and rearsurfaces of the diffuser 302 as the fluid travels through the diffuser302.

FIG. 4 illustrates a cross-sectional view of the diffuser 302 takenacross the A-A line. To control the fluid separation that occurs in thediffuser 302, a plurality of fluidic oscillators 200 are positionedabout a curvature of the diffuser 302. For example, the fluidicoscillators 200 may be positioned at the interface 311 of the diffuser302 and the inlet 310. Positioning the fluidic oscillators 200 at theinterface 311 allows the fluidic oscillators 200 to be positionedupstream of where separation is likely to occur. In another embodiment,the fluidic oscillators 200 may be positioned downstream of theinterface 311. The number of fluidic oscillators used may depend on anumber of factors, some of which include, the size and weight of eachfluidic oscillator, the size of the diffuser 302, and the degree of theflow separation. In the example shown in FIG. 4, about fourteen fluidicoscillators are arranged about the curvature transition of the inlet.

FIG. 5 illustrates a method 500 for managing flow of a fluid, accordingto one example. The method 500 begins at step 502.

At step 502, the fluidic oscillator receives a fluid flow into an inletformed in a body of the fluidic oscillator. The fluidic oscillator maybe part of an active flow control system for an aircraft having anairframe with an inlet configured for flight speeds ranging fromsubsonic to hypersonic. The fluidic oscillators may be mounted about acurvature transition of the inlet. The fluid control system isconfigured to control the aerodynamics of the aircraft.

At step 504, the fluid is transmitted from the inflow portion of thefluidic oscillator to a narrow nozzle inlet formed in the body oppositethe inflow portion, along a single fluid flow path. The single fluidflow path is formed by positioning the narrow nozzle inlet opposite theinflow portion of the fluidic oscillator. The fluidic oscillator doesnot contain a feedback control loop, which is necessary in traditionalfluidic oscillators. Thus, there is only a single path the fluid mayfollow when entering the body of the fluidic oscillator.

At step 506, a jet of fluid is created in a throat of a nozzle that isintegral with the body of the fluidic oscillator at the narrow nozzleinlet. The nozzle includes curved sidewalls, which, are integral withthe narrow nozzle inlet, and an outlet, which is formed opposite thenarrow nozzle inlet. The narrow nozzle inlet has a first diameter, whichis less than a diameter of the outlet of the nozzle. When the fluidpasses through the narrow nozzle inlet, at a minimum pressure ratio, ajet of fluid is created in the throat of the nozzle. The minimumpressure ratio chokes the throat of the fluidic oscillator. For example,a Mach number of unity is sufficient to choke the throat of the fluidicoscillator.

At step 508, the jet of fluid is caused to exit the nozzle in adirection that changes periodically with time. The formation of the jetin the throat of the nozzle, between the curved sidewalls, allows thejet of fluid to exit the nozzle in an oscillating matter. This is due tothe space formed between the jet and the sidewalls of the nozzle byangling the sidewalls with respect to the narrow nozzle inlet. In oneembodiment, the angle between the curved sidewalls and the narrow nozzleinlet is less than 90°. In a specific embodiment, the angle between thecurved sidewalls and the narrow nozzle inlet is about 31°. Increasing ordecreasing the angle between the curved sidewalls and the narrow nozzleinlet will increase or decrease the frequency at which the jetoscillates upon exit of the nozzle.

When the jet of fluid exits the nozzle, the fluidic oscillator mayoperate in two specific modes: a sweeping mode and a shedding mode. Whenthe plume in the jet of fluid separates from the nozzle sidewalls, thiscauses the fluidic oscillator to operate in a sweeping, or low frequencymode (e.g., 10 kHz). As a result, the jet of fluid exiting the nozzlewill sweep from side to side with a small angular amplitude (e.g., lessthan 20° from peak to peak). When the plume begins to break-up, orexpand, from the jet of fluid, the fluid oscillator operates in ashedding, or high frequency mode (e.g., 200 kHz). The plume “sheds,”resulting in the spatial and temporal rapid mixing of the jet-energywith the surrounding flow field.

The formation of a single fluid flow path between the inflow portion andthe narrow nozzle inlet increases vehicle integration potential andreduces fabrication complexity and cost compared to conventional flowcontrol systems. The simplified fluidic oscillator works as efficientlyas the conventional fluidic oscillator at a fraction of the size andweight of the conventional oscillator. Thus, the gains from utilizing asingle fluid flow path are realized without compromising the benefit ofthe jet exiting the nozzle of the fluidic oscillator.

The descriptions of the various embodiments of the present inventionhave been presented for purposes of illustration, but are not intendedto be exhaustive or limited to the embodiments disclosed. Manymodifications and variations will be apparent to those of ordinary skillin the art without departing from the scope and spirit of the describedembodiments. The terminology used herein was chosen to best explain theprinciples of the embodiments, the practical application, or technicalimprovement over technologies found in the marketplace, or to enableothers of ordinary skill in the art to understand the embodimentsdisclosed herein.

In the following, reference is made to embodiments presented in thisdisclosure. However, the scope of the present disclosure is not limitedto specific described embodiments. Instead, any combination of thefollowing features and elements, whether related to differentembodiments or not, is contemplated to implement and practicecontemplated embodiments. Furthermore, although embodiments disclosedherein may achieve advantages over other possible solutions or over theprior art, whether or not a particular advantage is achieved by a givenembodiment is not limiting of the scope of the present disclosure. Thus,the following aspects, features, embodiments, and advantages are merelyillustrative and are not considered elements or limitations of theappended claims except where explicitly recited in a claim(s). Likewise,reference to “the invention” shall not be construed as a generalizationof any inventive subject matter disclosed herein and shall not beconsidered to be an element or limitation of the appended claims exceptwhere explicitly recited in a claim(s).

Aspects of the present invention may take the form of an entirelyhardware embodiment, an entirely software embodiment (includingfirmware, resident software, micro-code, etc.) or an embodimentcombining software and hardware aspects that may all generally bereferred to herein as a “circuit,” “module” or “system.”

While the foregoing is directed to embodiments of the presentdisclosure, other and further embodiments of the disclosure may bedevised without departing from the basic scope thereof, and the scopethereof is determined by the claims that follow.

What is claimed is:
 1. A flow control system for an aircraft, the flowcontrol system comprising: an airframe having an inlet configured forflight speeds ranging from subsonic to hypersonic; and a plurality offluidic oscillators mounted about a curvature of the airframe, eachfluidic oscillator comprising: a body comprising: an inflow portion influid communication with the inlet; and an aperture formed opposite theinflow portion, wherein the body is dimensioned to form a single fluidflow path from the inflow portion to the aperture; and a nozzleintegrated with the body, the nozzle comprising: a plurality of curvedsidewalls extending from a nozzle inlet disposed at the aperture to anoutlet opposing the nozzle inlet, wherein the curved sidewalls are bowedoutward from a perimeter of the nozzle inlet, wherein a first diameterof the nozzle inlet is less than a second diameter of the outlet, andwherein the curved sidewalls extend from the nozzle inlet at anglesselected such that the nozzle is configured to form an oscillating jetof fluid provided via the single fluid flow path.
 2. The flow controlsystem of claim 1, wherein a throat of the nozzle is defined between thecurved sidewalls, and wherein the first diameter of the nozzle inlet isselected such that, for pressures meeting a predefined pressure ratio,the oscillating jet of fluid is formed in the throat.
 3. The flowcontrol system of claim 2, wherein at the pressures meeting thepredefined pressure ratio, a velocity of the fluid at the throat isMach
 1. 4. The flow control system of claim 1, wherein the formation ofthe single fluid flow path enables a size of the fluidic oscillators tobe reduced by at least a factor of 2, when compared with an alternateimplementation of the fluidic oscillators having a feedback control loopformed in the body thereof.
 5. The flow control system of claim 1,wherein the formation of the single fluid flow path enables a weight ofthe fluidic oscillators to be reduced by at least a factor of 2, whencompared with an alternate implementation of the fluidic oscillatorshaving a feedback control loop formed in the body thereof.
 6. The flowcontrol system of claim 1, wherein the angles are less than 90 degreesfrom a line extending perpendicularly from the perimeter of the nozzleinlet toward the outlet.
 7. The flow control system of claim 6, whereinthe angles are about 31 degrees from the line.
 8. The flow controlsystem of claim 1, wherein the nozzle is dimensioned such that theoscillating jet of fluid oscillates according to at least a first,sweeping mode caused by a plume of the oscillating jet separating fromthe curved sidewalls.
 9. The flow control system of claim 8, wherein thenozzle is dimensioned such that the oscillating jet of fluid oscillatesaccording to a second, shedding mode caused by a break-up of the plume,wherein a frequency of the second, shedding mode is greater than afrequency of the first, sweeping mode.
 10. The flow control system ofclaim 1, wherein the aircraft comprises a wing and a compressor, whereinthe airframe comprises a diffuser positioned beneath the wing, whereinthe inlet is arranged at a first end of the diffuser, and wherein thediffuser is coupled with the compressor at an opposing second end. 11.An apparatus for managing flow control for an airframe during flight,the apparatus comprising: a body configured to connect with theairframe, the body comprising: an inflow portion; and an aperture formedopposite the inflow portion, wherein the body is dimensioned to form asingle fluid flow path from the inflow portion to the aperture at flightspeeds of the airframe ranging from subsonic to hypersonic; and a nozzleintegrated with the body, the nozzle comprising: a plurality of curvedsidewalls extending from a nozzle inlet disposed at the aperture to anoutlet opposing the nozzle inlet, wherein the curved sidewalls are bowedoutward from a perimeter of the nozzle inlet, wherein the outlet isarranged proximate to a surface of the airframe when the body isconnected with the airframe, wherein a first diameter of the nozzleinlet is less than a second diameter of the outlet, and wherein thecurved sidewalls extend from the nozzle inlet at angles selected suchthat the nozzle is configured to form an oscillating jet of fluidprovided via the single fluid flow path.
 12. The apparatus of claim 11,wherein a throat of the nozzle is defined between the curved sidewalls,and wherein the first diameter of the nozzle inlet is selected suchthat, for pressures meeting a predefined pressure ratio, the oscillatingjet of fluid is formed in the throat.
 13. The apparatus of claim 11,wherein the formation of the single fluid flow path enables a size ofthe apparatus to be reduced by at least a factor of 2, when comparedwith an alternate implementation having a feedback control loop formedin the body.
 14. The apparatus of claim 11, wherein the formation of thesingle fluid flow path enables a weight of the apparatus to be reducedby at least a factor of 2, when compared with an alternateimplementation haying a feedback control loop formed in the body. 15.The apparatus of claim 11, wherein the angles are less than 90 degreesfrom a line extending perpendicularly from the perimeter of the nozzleinlet toward the outlet.
 16. A method for managing flow of a fluid,comprising: receiving a fluid flow through an inflow portion formed in abody of a fluidic oscillator; transmitting the fluid flow along a singlefluid flow path from the inflow portion of the fluidic oscillator to anaperture formed in the body opposite the inflow portion; and forming, ina throat of a nozzle coupled with the body at the aperture, anoscillating jet of fluid from the fluid flow, wherein the nozzlecomprises a plurality of curved sidewalls extending from a nozzle inletdisposed at the aperture to an outlet opposing the nozzle inlet, whereinthe curved sidewalls are bowed outward from a perimeter of the nozzleinlet, wherein a first diameter of the nozzle inlet is less than asecond diameter of the outlet, and wherein the curved sidewalls extendfrom the nozzle inlet at angles selected such that the nozzle isconfigured to form an oscillating jet of fluid provided via the singlefluid flow path.
 17. The method of claim 16, wherein transmitting thefluid flow along the single fluid flow path enables a size of thefluidic oscillator to be reduced by at least a factor of 2, whencompared with an alternate implementation of the fluidic oscillatorhaving a feedback control loop formed in the body thereof.
 18. Themethod of claim 16, wherein the nozzle is dimensioned such that theoscillating jet of fluid oscillates in a first, low frequency mode inwhich the fluid exiting an outlet of the nozzle sweeps across theoutlet.
 19. The method of claim 16, wherein the nozzle is dimensionedsuch that the oscillating jet of fluid oscillates in a second, highfrequency mode in which the fluid exiting the outlet mixes jet-energywith a surrounding fluid flow-field.
 20. The method of claim 16, whereintransmitting the fluid flow along the single fluid flow path enables aweight of the fluidic oscillator to be reduced by at least a factor of2, when compared with an alternate implementation of the fluidicoscillator having a feedback control loop formed in the body thereof.